9.1 - Project Proposal.
[[Proposal 1 : Parachute]]
Introduction:
This project develops a steerable parachute system using a motor to rotate a weight in indexed increments, resetting to a neutral state using a mechanism turning a specific direction. This design allows for active center-of-gravity (CG) shifts across a nearly 360° range, enabling a "gimbaled" glide for precision flight controlled by the rotating weight.
Description of the Problem:
The Challenge: Achieving precise parachute control by rotating the center of gravity through 360° and generating tilt reactions with minimal mechanical input.
Proposed Mechanism:
To solve the challenge of active CG manipulation, this project proposes a dual-directional mechanism utilizing a motorized link with a weighted edge to control parachute tilt.
Clockwise Rotation (Active Steering): The motor allows the weighted link to rotate freely to any angle, providing continuous 360° directional control.
Counter-Clockwise Rotation (Neutral Reset): Reversing the motor engages a rachet and pawl mechanism. This specialized motion profile would activate a worm screw to lift the weight vertically though a slider(curtain) into a stable dwell position, acting as a "neutral" state.
Power Efficiency: By utilizing the intermittent motion of the rachet and pawl mechanism, the system maintains stability in the neutral state without requiring constant motor power until a new command shifts it back to a horizontal orientation for active tilting.
Scope of Work:
The project encompasses the design, analysis, and construction of a complete parachute tilt-control system, executed in three primary phases:
Phase 1: Proof-of-Concept Prototyping
Build a functional prototype of the dual-directional rachet and pawl mechanism.
Verify the mechanism's ability to reliably reset the weight to a vertical, neutral state.
Phase 2: Kinematic Analysis
Perform a rigorous kinematic evaluation of the system.
Calculate the Gruebler's equation to determine degrees of freedom and ensure mechanism stability under load.
Phase 3: Integration & Testing
Integrate the rachet and pawl into a physical parachute system.
Demonstrate active center-of-gravity manipulation during a simulated descent to validate the complex intermittent motion profile before finalizing the full robotic assembly.
Preliminary design ideas:
Alternative linkage which follows an arcing path.
[[Proposal 2: Origami]]
Introduction
Inspired by the self-folding robotics research from MIT and Harvard, this project aims to develop a minimalist, self-assembling robot that transitions from a flat 2D state into a functional 3D walking machine. While the original research utilized Shape Memory Polymers (SMPs) for heat-activated folding, this project will explore a purely mechanical actuation strategy. By using a single motor a 4-bar mechanism, the system will convert rotational torque into the multidimensional expansion of an origami-based chassis capable of terrestrial locomotion
Description of the Problem:
Target Challenge: The primary technical hurdle is achieving a 1-DOF (Degree of Freedom) Multi-Phase Actuation. To replicate the "flat-to-walking" transition, the robot must sequentially:
Transform: Lift its body from a 2D sheet into a 3D structure.
Locomote: Use the same motor input to drive a gait (dragging or walking).
Implementation Hurdles:
Motion Conversion: A 4-bar mechanism must reliably convert simple circular motor rotation into the synchronized "pop-up" expansion of multiple rigid-origami panels.
Mechanical Logic: Designing the linkage lengths and origami crease patterns to ensure the robot folds in the correct order, avoiding "binding" or structural jamming during the transition.
Torque Management: A single motor must overcome the initial "flat-state" resistance—where mechanical advantage is typically lowest—while maintaining enough power to drag the final 3D weight.
Proposed Mechanism
Power Generation & Transmission: The core uses a single DC motor or servo coupled with a Master Crank. This crank serves as the primary input for a 4-bar linkage system. This setup allows for rapid deployment compared to screw-based systems and utilizes the "toggle" position of the 4-bar to lock the structure in its 3D state without requiring continuous high-torque holding power.
Sequential Expansion (The 4-Bar Skeleton): Instead of a slider, the system uses a Coupler Link connected to Rocker Links (the origami legs).
Phase A (Deployment): As the master crank rotates, it pulls the coupler, forcing the rocker links to pivot upward. This movement triggers the sequential rotation and expansion of the rigid-origami panels along their crease geometry.
Phase B (Locomotion): Once the robot reaches its fully deployed 3D state, continued oscillation or rotation of the motor drives the 4-bar through its "rocking" arc, creating a rhythmic dragging motion to propel the design forward.
Rigid-Origami Chassis: The robot body consists of laser-cut rigid panels (3D printed, wood, acrylic, etc..) connected by flexible hinges. This mimics the "composite sandwich" approach seen in high-performance origami robots, ensuring the legs are stiff enough to support the motor's weight and aerodynamic or terrestrial loads.
Scope of Work
Phase 1: 4-Bar Kinematic Prototyping
Design and fabricate (via 3D printing) the Central Chassis, Master Crank, and Coupler Links.
Integrate the single motor to verify smooth rotational-to-angular conversion and validate the 1-DOF mobility (M=1) across the full range of motion.
Phase 2: Origami Structure & Linkage Integration
Fabricate the rigid-origami panels and thin hinges using laser cutting to ensure precise crease geometry and appropriate material yield strength.
Connect the Rocker Links to the origami nodes, confirming that the 4-bar effect reliably converts motor rotation into radial expansion without structural jamming.
Phase 3: Locomotion & Performance Validation
Evaluate the system's structural integrity, particularly the stress distribution at the primary hinge points, under simulated motor torque and movement loads.
Perform full transition tests to ensure a synchronized, continuous change from the compact 2D folded state to the fully expanded 3D walking state.
Preliminary design ideas:
Component | Function |
Central Chassis | The "Ground Link" of the 4-bar system that houses the motor and provides the fixed pivot points. |
Master Crank | The "Input Link" attached to the motor shaft that initiates the transformation. |
Coupler & Rockers | The "Floating Links" that translate the motor's circular path into the specific angular "step" of the legs. |
Hinge Geometries | Laser-cut paths that define the "foldability" and mechanical limit of each limb. |
References & Inspirations